3-Oxocyclohex-1-enyl 2-methoxy-3,6-dichlorobenzoate, and herbicidal use thereof

ABSTRACT

This invention discloses the compound 3-oxocyclohex-1-enyl 2-methoxy-3,6-dichlorobenzoate and its use as a herbicide.

This invention relates to a new composition of matter and morespecifically relates to the new chemical compound 3-oxocyclohex-1-enyl2-methoxy-3,6-dichlorobenzoate. The compound of the present invention isunexpectedly useful as a herbicide.

The preparation of the compound of the present invention is shown in thefollowing example.

EXAMPLE 1 Preparation of 3-Oxocyclohex-1-enyl2-Methoxy-3,6-dichlorobenzoate

1,3-Cyclohexanedione (11.2 grams; 0.10 mole), benzene (100 ml) andtriethylamine (11.1 grams; 0.10 mole) were charged into a glass reactionvessel equipped with a mechanical stirrer. 2-Methoxy-3,6-dichlorobenzoylchloride (23.85 grams; 0.10 mole) dissolved in benzene (20 ml) was thenadded dropwise with stirring. After the addition was completed thereaction mixture was first stirred at ambient temperature for a periodof about one hour and then at about 75°C for a period of about 20minutes. After this time the mixture was cooled to room temperature andwas filtered. The filtrate was stripped of benzene under reducedpressure to yield an oil as the residue. This oil was distilled underreduced pressure to yield the desired product 3-oxocyclohex-1-enyl2-methoxy-3,6-dichlorobenzoate having a boiling point of 199° to 200°Cat 0.45 mm of Hg pressure.

For practical use as a herbicide the compound of this invention isgenerally incorporated into herbicidal compositions which comprise aninert carrier and a herbicidally toxic amount of the compound. Suchherbicidal compositions, which can be called formulations, enable theactive compound to be applied conveniently to the site of the weedinfestation in any desired quantity. These compositions can be solidssuch as dusts, granules, or wettable powders; or they can be liquidssuch as solutions, aerosols, or emulsifiable concentrates.

For example, dusts can be prepared by grinding and blending the activecompound with a solid inert carrier such as the talcs, clays, silicas,pyrophyllite, and the like. Granular formulations can be prepared byimpregnating the compound, usually dissolved in a suitable solvent, ontoand into granulated carriers such as the attapulgites or thevermiculites, usually of a particle size range of from about 0.3 to 1.5mm. Wettable powders, which can be dispersed in water or oil to anydesired concentration of the active compound, can be prepared byincorporating wetting agents into concentrated dust compositions.

In some cases the active compound is sufficiently soluble in commonorganic solvents such as kerosene or xylene so that it can be useddirectly as a solution in these solvents. Frequently, solutions ofherbicides can be dispersed under superatmospheric pressure as aerosols.However, preferred liquid herbicidal compositions are emulsifiableconcentrates, which comprise the active compound according to thisinvention and as the inert carrier, a solvent and an emulsifier. Suchemulsifiable concentrates can be extended with water and/or oil to anydesired concentration of active compound for application as sprays tothe site of the weed infestation. The emulsifiers most commonly used inthese concentrates are nonionic or mixtures of nonionic with anionicsurface-active agents. With the use of some emulsifier systems aninverted emulsion (water in oil) can be prepared for direct applicationto weed infestations.

A typical herbicidal composition according to this invention isillustrated by the following example, in which the quantities are inparts by weight.

EXAMPLE 2 Preparation of a Dust

    Product of Example 1     10                                                   Powdered Talc            90                                               

The above ingredients are mixed in a mechanical grinder-blender and areground until a homogeneous, free-flowing dust of the desired particlesize is obtained. This dust is suitable for direct application to thesite of the weed infestation.

The compound of this invention can be applied as a herbicide in anymanner recognized by the art. One method for the control of weedscomprises contacting the locus of said weeds with a herbicidalcomposition comprising an inert carrier and as an essential activeingredient, in a quantity which is herbicidally toxic to said weeds, thecompound of the present invention. The concentration of the new compoundof this invention in the herbicidal compositions will vary greatly withthe type of formulation and the purpose for which it is designed, butgenerally the herbicidal compositions will comprise from about 0.05 toabout 95 percent by weight of the active compound of this invention. Ina preferred embodiment of this invention, the herbicidal compositionswill comprise from about 5 to about 75 percent by weight of the activecompound. The compositions can also comprise such additional substancesas other pesticides, such as insecticides, nematocides, fungicides, andthe like; stabilizers, spreaders, deactivators, adhesives, stickers,fertilizers, activators, synergists, and the like.

The compound of the present invention is also useful when combined withother herbicides and/or defoliants, dessicants, growth inhibitors, andthe like in the herbicidal compositions heretofore described. Theseother materials can comprise from about 5% to about 95% of the activeingredients in the herbicidal compositions. Use of combinations of theseother herbicides and/or defoliants, dessicants, etc. with the compoundof the present invention provide herbicidal compositions which are moreeffective in controlling weeds and often provide results unattainablewith separate compositions of the individual herbicides. The otherherbicides, defoliants, dessicants and plant growth inhibitors, withwhich the compound of this invention can be used in the herbicidalcompositions to control weeds, can include chlorophenoxy herbicides suchas 2,4-D, 2,4,5-T, MCPA, MCPB, alachlor, 4(2,4-DB), 2,4-DEB, 4-CPB,4-CPA, 4-CPP, 2,4,5-TB, 2,4,5-TES, 3,4-DA, silvex and the like;carbamate herbicides such as IPC, CIPC, swep, barban, BCPC, CEPC, CPPCand the like; thiocarbamate and dithiocarbamate herbicides such as CDEC,metham sodium, EPTC, diallate, PEBC, perbulate, vernolate and the like;substituted urea herbicides such as norea, siduron, dichloral urea,chloroxuron, cycluron, fenuron, monuron, monuron TCA, diuron, linuron,monolinuron, neburon, buturon, trimeturon and the like; symmetricaltriazine herbicides such as simazine, chlorazine, atraone, desmetryne,norazine, ipazine, prometryn, atrazine, trietazine, simetone, prometone,propazine, ametryne, and the like; chloroacetamide herbicides such asalpha-chloro-N, N-dimethylacetamide, CDEA, CDAA,alpha-chloro-N-isopropylacetamide, 2-chloro-N-isopropylacetanilide,4-(chloroacetyl)morpholine, 1-(chloroacetyl)piperidine, and the like;chlorinated aliphatic acid herbicides such as TCA, dalapon,2,3-dichloropropionic acid, 2,2,3-TPA and the like; chlorinated benzoicacid and phenylacetic acid herbicides such as 2,3,6-TBA, 2,3,5,6-TBA,dicamba, tricamba, amiben, fenac, PBA,2-methoxy-3,6-dichlorophenylacetic acid,3-methoxy-2,6-dichlorophenylacetic acid,2-methoxy-3,5,6-trichlorophenylacetic acid, 2,4-dichloro-3-nitrobenzoicacid and the like; and such compounds as aminotriazole, maleichydrazide, phenyl mercuric acetate, endothal, biuret, technicalchlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, diquat, erbon,DNC, DNBP, dichlobenil, DPA, diphenamid, dipropalin, trifluralin, solan,dicryl, merphos, DMPA, DSMA, MSMA, potassium azide, acrolein, benefin,bensulide, AMS, bromacil,2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione,bromoxynil, cacodylic acid, CMA, CPMF, cypromid, DCB, DCPA, dichlone,diphenatril, DMTT, DNAP, EBEP, EXD, HCA, ioxynil, IPX, isocil, potassiumcyanate, MAA, MAMA, MCPES, MCPP, MH, molinate, NPA, OCH, paraquat, PCP,picloram, DPA, PCA, pyrichlor, sesone, terbacil, terbutol, TCBA,brominil, CP-50144, H-176-1, H-732, M- 2901, planavin, sodiumtetraborate, calcium cyanamid, DEF, ethyl xanthogen disulfide, sindone,sindone B, propanil and the like.

Such herbicides can also be used in the methods and compositions of thisinvention in the form of their salts, esters, amides, and otherderivatives whenever applicable to the particular parent compounds.

Weeds are undesirable plants growing where they are not wanted, havingno economic value, and interfering with the production of cultivatedcrops, with the growing or ornamental plants, or with the welfare oflivestock. Many types of weeds are known, including annuals such aspigweed, lambsquarters, foxtail, crabgrass, wild mustard, fieldpennycress, ryegrass, goose grass, chickweed, wild oats, velvetleaf,purslane, barnyard grass, smartweed, knotweed, cocklebur, wildbuckwheat, kochia, medic, corn cockle, ragweed sowthistle, coffeeweed,croton, cuphea, dodder, fumitory, groundsel, hemp nettle, knawel,spurge, spurry, emex, jungle rice, pondweed, dog fennel, carpetweed,morningglory, bedstraw, ducksalad, naiad, cheatgrass, fall panicum,jimsonweed, witchgrass, switchgrass, watergrass, teaweed, wild turnipand sprangletop; biennals such as wild carrot, matricaria, wild barley,campion, chamomile, burdock, mullein, roundleaved mallow, bull thistle,hounds-tongue, moth mullein and purple star thistle; or perennials sucha white cockle, perennial ryegrass, quackgrass, Johnson grass, Canadathistle, hedge bindweed, Bermuda grass, sheep sorrel, curly dock,nutgrass, field chickweed, dandelion, campanula, field bindweed, Russianknapweed, mesquite, toadflax, yarrow, aster, gromwell, horsetail,ironweed, sesbania, bulrush, cattail, wintercress, horsenettle,nutsedge, milkweed and sicklepod.

Similarly, such weeds can be classified as broadleaf or grassy weeds. Itis economically desirable to control the growth of such weeds withoutdamaging beneficial plants or livestock.

The new compound of this invention is particularly valuable for weedcontrol because it is toxic to many species and groups of weeds while itis relatively nontoxic to many beneficial plants. The exact amount ofthe compound required will depend on a variety of factors, including thehardiness of the particular weed species, weather, type of soil, methodof application, the kind of beneficial plants in the same area, and thelike. Thus, while the application of up to only about 1 or 2 ounces ofthe active compound per acre may be sufficient for good control of alight infestation of weeds growing under adverse conditions, theapplication of 10 pounds or more of active compound per acre may berequired for good control of a dense infestation of hardy perennialweeds growing under favorable conditions.

The herbicidal toxicity of the new compound of this invention can beillustrated by many of the established testing techniques known to theart, such as pre- and post-emergence testing.

The herbicidal activity of the compound of this invention wasdemonstrated by experiments carried out for the pre-emergence control ofa variety of weeds. In these experiments small plastic greenhouse potsfilled with dry soil were seeded with the various weed seeds.Twenty-four hours or less after seeding the pots were sprayed with wateruntil the soil was wet and the test compound formulated as an aqueousemulsion of an acetone solution containing emulsifiers was sprayed atthe indicated concentrations on the surface of the soil.

After spraying, the soil containers were placed in the greenhouse andprovided with supplementary heat as required and daily or more frequentwatering. The plants were maintained under these conditions for a periodof from 15 to 21 days, at which time the condition of the plants and thedegree of injury to the plants was rated on a scale of from 0 to 10, asfollows: 0 = no injury, 1,2 = slight injury, 3,4 = moderate injury, 5,6= moderately severe injury, 7,8,9 = severe injury and 10 = death. Theeffectiveness of the compound is demonstrated by the following data:

                  TABLE I                                                         ______________________________________                                                  INJURY RATING                                                                 Concentration                                                                 (lbs./acre)                                                         Weed Species                                                                               4         2          1                                           ______________________________________                                        Yellow Nutsedge                                                                            6         0          0                                           Wild Oats    7         6          4                                           Jimsonweed  10         10         9                                           Velvetleaf  10         10         7                                           Johnsongrass                                                                               8         6          0                                           Pigweed     10         10         10                                          Mustard     10         10         10                                          Yellow Foxtail                                                                             9         8          4                                           Barnyardgrass                                                                             10         10         9                                           Crabgrass   10         8          5                                           Cheatgrass  10         8          4                                           Morningglory                                                                               9         9          9                                           ______________________________________                                    

The herbicidal activity of the compound of this invention was alsodemonstrated by experiments carried out for the post-emergence controlof a variety of weeds. In these experiments the compound was formulatedas an aqueous emulsion and sprayed at the indicated dosage on thefoliage of the weeds that have attained a prescribed size. Afterspraying the plants were placed in a greenhouse and watered daily ormore frequently. Water was not applied to the foliage of the treatedplants. The severity of the injury was determined 10 to 15 days aftertreatment and was rated on the scale of from 0 to 10 heretoforedescribed. The effectiveness of the compound is demonstrated by thefollowing data:

                  TABLE II                                                        ______________________________________                                                  INJURY RATING                                                                 Concentration                                                                 (lbs./acre)                                                         Weed Species                                                                               4         2          1                                           ______________________________________                                        Yellow Nutsedge                                                                            8         5          1                                           Wild Oats    8         9          5                                           Jimsonweed  10         10         10                                          Pigweed     10         9          8                                           Johnsongrass                                                                              10         8          5                                           Bindweed    10         10         10                                          Mustard     10         9          9                                           Yellow Foxtal                                                                              8         5          1                                           Barnyardgrass                                                                              9         8          8                                           Crabgrass    8         5          3                                           Morningglory                                                                              10         10         10                                          ______________________________________                                    

I claim:
 1. The compound 3-oxocyclohex-1-enyl2-methoxy-3,6-dichlorobenzoate.
 2. A herbicidal composition comprisingan inert carrier and, as an essential active ingredient, in a quantitytoxic to weeds, the compound of claim
 1. 3. A method of controllingweeds which comprises contacting the weeds with a herbicidal compositioncomprising an inert carrier and, as an essential active ingredient, in aquantity toxic to weeds, the compound of claim 1.